Another year, another record level for greenhouse gases in the atmosphere, according to the World Meteorological Organization.

The organization reported this week that the level of greenhouse gases detected in the air around the world in 2012 topped the previous record, set the year before. It continues "an upward and accelerating trend," it said.

Greenhouse gases haven't been this high in at least 800,000 years and will continue climbing unless something is done soon to curb emissions from burning fossil fuels, the agency said Wednesday.

Despite worldwide attention to the issue of global climate change, the pace at which carbon dioxide is being added to the atmosphere appeared to increase in 2012 and is now 141% of the pre-industrial level, the group said.

"The observations from WMO's extensive Global Atmosphere Watch network highlight yet again how heat-trapping gases from human activities have upset the natural balance of our atmosphere and are a major contribution to climate change," WMO Secretary-General Michel Jarraud said in a prepared statement.

The report follows another one issued Tuesday by the United Nations' Environment Programme indicating that swift action to limit emissions is necessary to hold down the cost of efforts to prevent global temperatures from rising more than 3.6 degrees (2 degrees Celsius).

The agency sets 2020 as the target for nations closing what it calls the "emissions gap" or face increased costs and narrowing options to keep temperature increases in check.